U.S. Pat. No. 3,123,939 issued March 1964 to the Generic Electric Company, discloses a connector system for mounting to a building wall the exhaust air duct from a clothes dryer. The exhaust air duct is anchored to the building wall by spaced annular flanges, which come in contact with a reinforcing panel, so that an intermediate chamber is defined between the annular flanges.
Canadian patent No. 1,240,548 issued 14 Aug. 1988 to Raymond CHOUINARD, shows at FIG. 1 the concept of providing a cylindrical housing for air exhaust from a clothes dryer, comprising a pair of sealing rings at its two opposite ends, being in contact with the cylindrical opening in the building wall.
One problem with these known wall connectors for mounting the outer end of a clothes dryer exhaust air duct to a building wall, is the difficulty of repairing the damaged external hood thereof. Indeed, it is a time-consuming operation, since for replacing the hood, it is usually required that the combination of the external hood and integral interior connector body needs to be pulled out from the building wall; or if the hood is detached from the cylindrical connector body, removal of the combined hood-connector body from the building wall usually leads to structural damage being made about the marginal wall section surrounding the wall aperture into which the connector body is mounted.
Before a fresh wall connector has been installed, a bricklayer has to repair the marginal brick wall portion--an additional labour cost expense. After installation of the fresh wall connector, new caulking must be applied around the hood, to seal the joint between the hood and the building wall. Also, during repairs in cold weather, condensation may occur between the brick wall and gyproc wall, and this condensation may eventually lead to structural damage to the building and.backslash.or to the inside furniture of the occupant. Finally, for the worker himself, the working conditions are often harsh in cold sub-freezing winter months, when he has to work outside the house with his feet deep into snow.
A second drawback of existing clothes dryer air exhaust duct wall connectors is that, during early construction phase of the building when only the outer brick wall is being laid exclusively of the inner finish gyproc wall, it will not be possible for the bricklayers to install the connector and the hood in a permanent fashion. This will have to be done at a later step of building construction, when the bricklayers will have to come back later for completing the installation job of the hood, thus again increasing labour costs. Indeed, during installation of the gyproc wall, it is understood that the connector will have to be temporarily removed; removal of connector will be effected by pulling same interiorly. Accordingly, the gap between the exterior brick wall and the interior gyproc wall will again become exposed to outside ambiant air, leading to air inflow leaks. In cold winter months, this leads to undesirable condensation between the brick wall and gyproc wall.